f(x) = x /2 +1
f(1 ) = 1/2 +1
f(3 ) = 3/2 + 1
.....................
f( 2013 ) = 2013 /2 + 1 ; o suma cu 1007 termeni
n = ( 1+3+5+ ........+ 2013 ) /2 + 1·1007 =( 1 + 2013 ) ·1007 / 2· 2 +1007 =
= 2014 ·1007 / 4 + 1007 = 1007² ·/2 +1007
2n - 2014 =1007² + 2·1007 - 2014 =1007² + 2014 - 2014 = 1007²patrat perfect
